Hydroaircraft.



@G. H. CIURIISS.

1,296,630. I9. I Patented Mar. 11,1919.

V ZSHEETS-SHEET l.

G. H. CURTISS.

HYDROAIRCRAFT.

APPLICATION FILED- FEB. 28. 1917.

v Patented Mar. 11, 1919.

- 2 SHEETS-SHEET Z.

GLENN H Cue-r155.

GLENN H. CURTISS, OF BUFFALO, NEW YORK, ASSIGNOR T GURTISS AEROPLANE AND MOTOR CORPORATION, A CORPORATION OF NEW YORK.

HYDROAIRCRAFT.

To all whom it may concern:

Be it known that I, GLENN H. CURTISS, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented certain new and useful Improvements in Hydroaircraft, of

while skimming thereover.

"which the following is a specification.

My invention relates to aircraft and has 7 reference more particularly to hydroaero- 10 planes and flying boats in which the pontoon of the former and the'hull'of the latter are equipped with elongated longitudinally nonsalient bottoms imparting such stability to the craft that it can not oscillate about a transverse axis while traveling at speed on the surface of the water and preparatory to aerial flight.

Most, if not all successful hydroaeromachines have heretofore been characterized by one or more flotation .bodies having a lower surface off-longitudinal saliency extended rearwardly considerably beyond the transverse vertical plane of the center of gravity'or with a surface so constructed that its rearwardterminus acts as a transverse edge about" which the craft may be rocked.

In this way, after gaining speed and 'while hydroplaning, the angle of incidence of the supporting surfaces may be' fuddenly increased by depressing the tai end of the craft, and the necessary lift obtained to pull the machine from the surface of the water oscillation abouta transverse edge or step in the vicinity of. the transverse vertical plane of the center of gravity has been relied-on to secure the necessary vertical lift in taking tothe air from the surface of the cidence, 2'. e.,the angle giving the max w water.

By the present invention it is proposed to deviate or depart from the standard practice and instead rovide a machine in which the bottom sur ace is non-salientand the aeroplane wings. or supporting surfaces fixed, permanently in such relation to the flotation body as to make an angle with the keel line equal to the calculated angle of inmum lift-drift 1 ratio or. a ratio suflicient to pull the craft-from the surface of the water without rocking the body fore and aft.

The invention is further characterized by shaping the body of a symmetrical streamline form about an axis-making with the Specification of Letters Patent.

Fore and aft .at an angle thereto, forwardly and downwardly inclined, and not greater than the i ngle which said body makes with the keel lne.

Of the drawings, wherein like characters of reference designate like or corresponding parts:

Figure 1 is a side elevation of a hydroaeroplane characterized as herein pointed out;

Fig. 2 is a similar view illustrating the machine positioned for maximum climbing efliciency;

Fig. 3 is a view similar to Fig. 1 illustrating a flying boat, and

Fig. 4 illustrates the flying boat in a manner similar to the illustration of Fig. 2.

In the embodiment of the invention selected for illustration, 10 designates the fuselage, 11 the pontoon or flotation body, 12 the supporting surfaces, 13 the empenna e, and 14 the propelling power plant of a hy roaeroplane ca able of gaining aerial flight from the sur ace of the water without Patented Mar. 11, 1919.

Application filed February 28, 1917. Serial No.151,504. l

Fore and aft oscillation of the craft with the nated 20 equalto the maximum flying angle of incidence, 2'. 6., the angle giving the maximum lift drift ratio or at least a lift-drift ratio sufficient to pull the, boat fnom the surface of the water while skimming thereover. h The pontoon 11 is symmetrically stream-.

lined about an axis 21 making with the prevented. In other be describedas I chord line 22 0f the'supporting surfacesan angle equalto the flying'angle of incidence for maximum speed or at least for -a. liftd-rift ratio considerably less than maximum,

The keel line thus makes with the axis 21 an angle greater than the angle of inci dence for maximumspeed- The line of thrust of the 20 indicating the keel line of the pontoon.-

v angle formed In other words, the interior angle formed by the line of thrust, designated 23 and the'line- 2-1, is never to be greater than the interior by said line 21 'and the keelline 20.

For an understanding of theiprinciples' here involved, I have assumed that the angle of incidence for maximum speed is two (29) degrees and that the angle of incidence for maximum climb is eight and a half (85 degrees ried). Six and a half (6-?) degrees or the difference between the angle of incidence for maximum speed and the angle of incidence for maximum lift I have calculated as best for the angle formed by the lines 21 and 20 indicating respectively the axis of the pontoon 11 and the keel line thereof. When at rest upon the surface of the water and unsupported by air reaction on the surfaces 12, the lower half of the pontoon is completely submerged. After starting, and as the machine speeds up, the hydroplaning bottom of the pontoon 12 causes the machine to gradually shift from the position indicated in Fig. 1 to the position indicated in Fig. 2, the latter (Fig.2) indicating the position of, the

craft at high speed and supported principally by air reaction on the surfaces 12,

4 although still hydroplaning lightly on the surfa'ce'of the water. As the position of the machine is gradually shifted, the angle of incidence of the supporting surfacesv 12 is gradually increasedfrom two (2) degrees to eight and a half (,8?) degrees, the latter angularity having been calculated to exert su cient lift to pull the boat .from the sur- 1 face of the water while skimming thereover and without rocking the craftfore and aft. This angle of incidence (8%") determinesnot only the angularity required to rise from the surface of the water but the angularity calculated as best for maximum climb. At

all. times, under the conditions stated, the

' effective line of thrust 23 and the axis '21 extend parallel and since the pontoon 11 isboat, 31 the, supporting surfaces, 32 the emcraft arranged parallel-to said axis 21 or at least at (both of these, angles may be va-- pennage, and 3;; the support for the propelling power plant (not shown). The hydroplaning bottom of the hull 30, like the bottom of the pontoon 11, is longitudinally non-salient, thus" imparting such stability to the boat that it cannot be rocked about a. transverse axis while h'ydroplaning; at speed. Said bottom is stepped-at intervals longitudinally as'indicated at 44 to insure hydroplaning action and reduce suction and skin friction. The arrangement and location of the steps may be varied as desired. The lines indicating respectivey the keel line, the hull fore and aft axi 1 line, and thechord line of the surfaces 31 I have designated 4Q, 41 and 42. These lines are disposed and related as pointed out hereinbefore; i

By an arrangement of the-various lines in .v the manner stated,"aerial flight from-the surface of the water can behad without depressin" the tail of the-craft before getting ofi of t e water and without ofi'erin unnecessary resistance after aerial flight as been gained. A perfect streamlining of the flotation body is possible so long asthe fore and aft axis of said body is in parallelism I with the corresponding axis of the fuselage 10 (in an hydroaeroplane) or the effective line of thrust. The location of the step with respect to the center of gravity is immaterla In using the term keel line herein I refer moreparticularly to a straight line joinin the projecting points of the float bottom.

, Vhile I have herein illustrated and described certain specific measurements, it is to be understood that these measurements are given only as illustrative ofan operative machine. characterized as herein described, These measurements may be varied considerably without departing from the spirit of the invention. Limitations other than such as are imposed by the claims are not intended to be made. Hencez What is claimed is: n

1. In an aircraft, a flotation body having a non-salient bottom, a motor, and supporting surfaces fixed permanently in such relation to said flotation body as to'make an angle 115 with the keel line thereof equal at least'to the angle of incidence calculated to give a lift-drift ratio suflicient to pull the craft from the surface of the water without rocking said body fore and aft. 1'20 2. In an aircraft, a flying boat having a longitudinallynon-salient bottom, a motor, and supporting surfaces fixed permanently in such relation to said flotation body as to make an angle. with the keel line thereof 125 equal to the angle of incidenceealculated for -maximum effective lift.

3s In an. aircraft, supporting surfaces, a

motor, and a flotation'body having a symmetricalstreamline formed about an axis making with the chord line of said sup ort ing surfaces an angle equal to the ying angle'of incidence for maximum speed.

4. In an aircraft, supporting surfaces, a motor, and a flotation body having a symmetrical streamline formed about an axis makin with the chord line of said supporting surfaces an angle equal to the flying angle of incidence for a lift-drift ratio con siderably less than maximum. I 1

In a hydro-aero-machine, supporting surfaces, a propelling power plant, and a flotation body having a symmetrical streamline formed about an axis making with the chord line of said-supporting surfaces an angle not greater than the angle formed by said axial line and the keel line of said body.

(3. In a hydro-aero-machine, supporting surfaces, a flotation body having a longitudinail non-salient bottom and a symmetrical streamline formed about an axis making with the chord line of said supporting surfaces an angle equal to the flying angle of incidence calculated for maximum speed,said surfaces bein fixed permanently insuch-res 35 lation to sai flotation body as to make' an" angle with the keel line thereof at least equal to the angle of incidence calculated givea lift-drift ratio sufiici'ent to 'pu1 l thefcraft; from the surface of the water'ia'vithout rock? ing said body fore and aft; 7. In a hydroaeroplane,. supporting surfaces, a pontoon having a syin! ne tri calf.v

streamline formed about an a x isvr'naking'-- with the chord line of said supporting s'urj faces an angle equalto theflyi'ng angle of incidence formaximum speed; and'fa propelling :power plant having its effective thrust I line in parallelism with said pontoo'ri' axis. f-

In testimony whereof I hereunto aflik my 40 signature.

EURTISS. 

